【发布时间】：2018-10-05 18:52:15
【问题描述】：
完全披露：我的问题可能是基于对 Xen Desktop 的 Citrix PowerShell 模块的不完全理解。
我有以下脚本块。它在一个循环中被调用，对列表中的每个 VM 调用一次。我使用 PowerShell Jobs 是因为我想在作业运行时保持 UI 线程空闲以更新 UI。
代码“A”
$j = Start-Job -Name $jobName -ScriptBlock {
param($url, $uuid, $cred, $snapshotName)
$ErrorActionPreference = "Stop"
try
{
$error.clear()
$xSS = $cred | Connect-XenServer -url $url -NoWarnCertificates -SetDefaultSession -PassThru;
$vm = (Get-XenVM -SessionOpaqueRef $xss.opaque_ref -uuid $uuid)
#Create snapshot
Invoke-XenVM -Async -SessionOpaqueRef $xss.opaque_ref -VM $vm -XenAction Snapshot -NewName $snapshotName
return "OK"
}
catch
{
return ("ERROR: "+$error)
}
} -ArgumentList $global:configFileVmMetaData.poolUrl, $xenVm.key, $global:cred, $snapshotName
代码“A”可以正常工作，但它需要的时间比必要的要长，因为我每次调用脚本块时都在执行Connect-XenServer cmdlet。
所以，我尝试在循环外调用Connect-XenServer 并传入会话变量，如下面的代码“B” 所示。结果是错误Could not find open sessions to any XenServers 被抛出到脚本块中。我假设 $xss 会话变量在传递到脚本块时会以某种方式受到影响。
知道为什么 $xss 会话变量会被改变吗？
代码“B”
$xSS = $cred | Connect-XenServer -url $global:configFileVmMetaData.poolUrl -NoWarnCertificates -SetDefaultSession -PassThru;
loop
{
$j = Start-Job -Name $jobName -ScriptBlock {
param($xss, $uuid, $snapshotName)
$ErrorActionPreference = "Stop"
try
{
$error.clear()
$vm = (Get-XenVM -SessionOpaqueRef $xss.opaque_ref -uuid $uuid)
#Create snapshot
Invoke-XenVM -Async -SessionOpaqueRef $xss.opaque_ref -VM $vm -XenAction Snapshot -NewName $snapshotName
return "OK"
}
catch
{
return ("ERROR: "+$error)
}
} -ArgumentList $xss, $xenVm.key, $snapshotName
}
受
Robert Cotterman答案启发的其他示例在所有情况下，我仍然收到
Could not find open sessions to any XenServers错误仅供参考 - 使用 PowerShell 5.1
使用$using 的示例。变量内容按预期传入和传出
cls
$aLocal = "AAA"
$bLocal = "BBB"
$j = Start-Job -Name "TestJob" -ScriptBlock {
return ($using:aLocal + " *** " + $using:bLocal)
}
while ($true)
{
$g = get-job -name "TestJob"
write-host ("get-job " + $g.Name + " is " + $g.State)
if ($g.State -ne "Running")
{
break
}
start-sleep -Seconds 1
}
write-host ("receive-Job='" + (receive-Job -Name "TestJob") +"'")
$g = get-Job -Name "TestJob"
Write-Host ("get-Job "+$g.name + " " + $g.state + " " + $g.HasMoreData + " " + $g.id)
if($g)
{
Remove-Job -Name "TestJob"
}
输出
get-job TestJob is Running
get-job TestJob is Completed
receive-Job='AAA *** BBB'
get-Job TestJob Completed False 45
Remove-Job
使用 args 的示例。变量内容按预期传入和传出
cls
$aLocal = "AAA"
$bLocal = "BBB"
$j = Start-Job -Name "TestJob" -ScriptBlock {
return ($args[0] + " *** " + $args[1])
} -ArgumentList ($aLocal, $bLocal)
while ($true)
{
$g = get-job -name "TestJob"
write-host ("get-job " + $g.Name + " is " + $g.State)
if ($g.State -ne "Running")
{
break
}
start-sleep -Seconds 1
}
write-host ("receive-Job='" + (receive-Job -Name "TestJob") +"'")
$g = get-Job -Name "TestJob"
Write-Host ("get-Job "+$g.name + " " + $g.state + " " + $g.HasMoreData + " " + $g.id)
if($g)
{
Remove-Job -Name "TestJob"
}
输出
get-job TestJob is Running
get-job TestJob is Completed
receive-Job='AAA *** BBB'
get-Job TestJob Completed False 49
使用命名参数的示例。变量内容按预期传入和传出
cls
$aLocal = "AAA"
$bLocal = "BBB"
$j = Start-Job -Name "TestJob" -ScriptBlock {
param($a, $b)
return ($a + " *** " + $b)
} -ArgumentList ($aLocal, $bLocal)
while ($true)
{
$g = get-job -name "TestJob"
write-host ("get-job " + $g.Name + " is " + $g.State)
if ($g.State -ne "Running")
{
break
}
start-sleep -Seconds 1
}
write-host ("receive-Job='" + (receive-Job -Name "TestJob") +"'")
$g = get-Job -Name "TestJob"
Write-Host ("get-Job "+$g.name + " " + $g.state + " " + $g.HasMoreData + " " + $g.id)
if($g)
{
Remove-Job -Name "TestJob"
}
输出
get-job TestJob is Running
get-job TestJob is Completed
receive-Job='AAA *** BBB'
get-Job TestJob Completed False 55
【问题讨论】：
-
我只是不认为它是这样工作的。为您的 PowerShell 会话创建与 Xen 服务器的连接，并在
$xss变量中收集有关该连接的信息。每个作业都运行自己的 PowerShell 会话。所以只是将$xss传递给作业是不一样的，它只是对连接细节的描述。换句话说，我可以写下关于我的汽车的所有细节并交给你，但你不能开车去上班。 -
同意。我需要重新考虑这一点。请作为答案发布
-
powershell 有一个内置的作业等待。
get-job | wait-job
标签： powershell scope xen scriptblock